Diamond-holding tool



March 10, 1942. 1 D|NHQFER 2,275,512

DIAMOND-HOLDING TOOL Filed May 20, 1941 @may Patented Mar.` 10, 1942 UNITED STATES PATENT VOFFICE `2,275,512 f DIAMOND-HOLDING Tool.

Julius Dnhofer, New York, N..Y. Application May 20, 1941, Serial No. 394,275

. 1 Claim. This invention relates to `diamond-holding tools` `of the character employed for grinding At the present time, diamonds used for grind-` ing or dressing purposes are usually of irregular shape and because of this are ,mounted with diliiculty in holders in which it is `necessary for them to be securely held during the hard use to which tools of this character are put. I Inmy co-pending applications above mentioned, it is proposed that the diamonds be rst ground to a regular form, or octahedral, to enable` `them to be securely gripped in a specially designed holder. This requires considerable grinding which adds to the cost of production. The present invention is intended to reduce the amount of grinding on the diamond, and simplify the holder in which the same is mounted so that a relatively inexpensive but thoroughly practical tool is produced. `More particularly, the invention contemplates theprovision of a diamond ground to provide two substantially conical pointed ends, and a holder in which one of said ends is seated, said holder being provided with a cap, apertured to permit the projection` of the second pointedlend, and acting to securely clamp the diamond on the seat and hold it against displacement.

In the accompanying drawing, wherein an embodiment of the` invention is shown, Fig. 1 is asectional View of a diamondholding tool constructed in accordance with the invention; Fig.2 is a side elevation of the same; Fig. 3 is a side View of one end of the tool, with the cap thereof removed and shown in section; and Fig. 4 is a plan view of the tool.

The diamond for use in the tool is prepared by to enable the same to be securely gripped and held against displacement during the hard use to which a tool of this character is subjected.` I

, find it desirable to grind the unfinished or rough fa relatively small amount of grinding in order diamond into the shape shown in Fig. 1 wherein ing merely desirable that the diamond shall have two usable pointed ends and adjacent substantially conical portions for engagement by parts of the holder as will be hereinafter pointed out.

The holder includes a3rod or stem portion 5 provided with a knurled portion 6, a threaded portion I `and a head 8. The head is formed with a recess 9, the same constituting a shallow depression of substantially circular shape, the marginal edge I0 of said recess constituting a seat for the diamond. It is desirable, although not absolutely necessary that the recess Il) shall be of less diameter than the widest diameter of the diamond. If the diamond employed is of larger diameterthan the recess I0 it will have its lower cone-shaped portion 4 seated upon the edge of the recess. If it is of larger diameter, the lower pointed end can rest against the bottoml of the recess I0.

The means for holding the diamond in the `holder comprises a clamping member or cap II which` is knurled at I5 and internally threaded as at I2 for adjustable reception upon the threaded portion 'I of the holder. 'Ihe cap has an inclined end wall I3 formed with a central circular opening I4 of a diameter less than the widest diameter of the diamond. When the cap is in position, it will be seen that one of the conical ends of the diamond, namely, that shown `at 3, will protrude through the opening I4 so that the point I of the diamond will project beyond the end wall 9 of the cap `and be available for use against a grinding wheel or for any other purpose. The end Wall I3 of the cap is tapered and is made relatively thin adjacent to the central opening so that when the cap is tightened down, the thin and slightly elastic edge of the` opening I4 will be forced tightly against the conical surface ofthe cone-shaped portion 3 of the diamond so that the diamond will not only become wedged in the opening I4 and `held against rotative movement, but will also be rmly held against the seat I0 or in the recess around which said seat extends.

When the projecting end I of the diamond becomes worn after considerable use, the cap II is removed, andwhen this is done, the diamond, being wedged in opening I4, is usuallylifted oi the holder with the cap. The knurling t` and I5 on the holder and cap II, respectively,`aids '2 i grinding; the tool consists of only two parts, exclusive of the diamond, and will last indefii nitely since a new 'diamond can be replaced in it Whenever necessary. Also, since the diamond kcan be reversed when one of the pointed ends becomes Worn, the tool need never leave the possession of its user.

What I claim is:

In a tool of the character described, a diamond having two substantially coned ends, each l0 end terminating in a point, a holder having a recess in its end in which one of the coned ends of the diamond seats, a cap adjustable on said,` holder, said cap having a conical and integral the holder.

end wall formed with a centrally located circular opening through which the second coned end of the diamond extends, said conical end wall JULrUs DI'NHOFER. 

